There is a constant demand for smaller electronic components and/or modules, particularly in the aircraft or aerospace fields, where size and weight are of critical importance. Microelectronics offers a great reduction in size and weight of electronic components where the components are mounted on boards including integrated circuitry.
One of the first steps in size and cost reduction was the modular concept where electronic plug-in modules were developed to meet various system requirements. Standard hardware designs were provided to have a plurality of modules which plug in a chassis to form an assembly. Normally, these plug-in modules slide in grooves in the chassis and engage a mating female electro-optical connector accessing the module to a mother board electro-optical back plane. These modules are closely assembled and dissipate considerable heat which, if not removed efficiently, greatly affects component reliability.
This problem of dissipating heat has been approached by various attempts to cool the electronic assemblies, ranging from some type of cooling fan assembly to cooling coils.
One approach for improving the cooling arrangement for an electronic plug-in module assembly is shown in U.S. Pat. No. 4,315,300 to Parmerlee et al, dated Feb. 9, 1982. This patent shows an arrangement where a plurality of modules are supported in grooves defined by a pair of parallel sides of a chassis. Each parallel side is provided with fluid passageways for carrying a cooling liquid for removing heat transferred from a heat sink on each module to the sides of the grooves. A plurality of apertures are provided in each side between adjacent grooves and carry fins through which cool air is blown to cool each side of each plug-in module. Such arrangements may be adequate, advanced some electronic components, but it simply is insufficient for advanced components, such as "supercomputers", advanced radar or other systems where 200-500 watts of heat are anticipated to be generated by each module.
Another approach to solving the problem of dissipating heat from electronic circuit components is shown in the cooling system of U.S. Pat. No. 4,712,158 to Kikuchi et al, dated Dec. 8, 1987. This patent discloses a cooling system for electronic circuit components mounted on a printed circuit board and includes a cooling plate having a coolant passage, with thermal contacts arranged on the cooling plate in contact with the surfaces of the electronic components. The components are cooled through the thermal contacts by liquid coolant flowing through the coolant passage. The coolant enters the cooling plate through an inlet and continuously flows through the plate and is discharged through an outlet. Such a system is extremely leak prone, particularly when one considers the number of modules that may be plugged into a chassis and the network of "plumbing" required to provide a circuit for the moving coolant.
This invention is directed to solving this problem of cooling electronic components by providing a cold plane with a self-contained cooling network of liquid coolant in a reflux, boiling and condensing, manner.